1. Field of the Invention
This invention relates to a wafer gripping device for a semiconductor fine working device, such as an etching device, ion inplanting device, etc., having an auxiliary vacuum chamber suitable for automatically feeding a wafer from the auxiliary vacuum chamber to a vacuum chamber or in discharging same therefrom.
2. Description of the Prior Art
Heretofore, one type of wafer gripping device for a semiconductor fine working device uses a vacuum chuck system. Another type uses a gripping mechanism including claws. Still another type uses a wafer scooping system using a wafer push-up mechanism in combination. Of all these types, many of them are of the construction that the wafer is attracted under atmospheric pressure after the vacuum chamber is turned into an atmospheric chamber, so as to supply or discharge the wafer.
In the type of wafer gripping device using the gripping mechanism including the claws, a power transmitting system is used which relies on gears for vertically moving the claws to open and close the same. Since no dust preventing means are provided dust collects and the material has a low yield in a semiconductor working operation in which fine working on the order of sub microns is carried out. In the wafer gripping device using a wafer push-up mechanism, the problem is raised that uniformity of etching is lacking in an etching operation due to the need to form a cutout opening in the lower electrode.
Some devices use a guide ring for the wafer to increase uniformity of etching in the etching operation. However, when the vertical stroke of the claws is small, it is impossible to grip the wafer by the claws because the claws pass by the guide ring.